Synthesis of (±)‐cis‐1‐Aryl‐3‐oxo‐2,3‐dihydro‐1H‐benzo[f]chromene‐2‐carbonitriles and (±)‐trans‐4‐Aryl‐2‐oxo‐3,4‐dihydro‐2H‐benzo[h]chromene‐3‐carbonitriles

Abstract

The unexpected stereospecific synthesis of (±)‐cis‐1‐aryl‐3‐oxo‐2,3‐dihydro‐1H‐benzo[f]chromene‐2‐carbonitriles (2) and (±)‐trans‐4‐aryl‐2‐oxo‐3,4‐dihydro‐2H‐benzo[h]chromene‐3‐carbonitriles (4) from (±)‐3‐amino‐1‐aryl‐1H‐benzo[f]chromene‐2‐carbonitriles (1) and (±)‐2‐amino‐4‐aryl‐4H‐benzo[h]chromene‐3‐carbonitriles (3), respectively, by reacting them in formic acid (88%), at reflux, is reported. A DFT analysis has been applied with success to justify these highly stereospecific reactions.